W97M.Lunedo.B

SUMMARY

W97M.Lunedo.B is a macro virus that infects Microsoft Word documents. It deletes files, modifies system settings, and lowers security settings on the compromised computer.

Protection

• Virus Definitions (LiveUpdate™ Daily) May 25, 2006
• Virus Definitions (LiveUpdate™ Weekly) May 31, 2006
• Virus Definitions (Intelligent Updater) May 25, 2006
• Virus Definitions (LiveUpdate™ Plus) May 25, 2006

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Medium
• Payload: Deletes files and lowers security settings.

Distribution

• Distribution Level: Low
• Target of Infection: Infects Word documents.

TECHNICAL DETAILS

When an infected Word document is opened, W97M.Lunedo.B performs the following actions:

1. Displays a message box with the following properties:
   
   Title:
   CD Music
   Message:
   Listen your musics.
   
   
2. Repeatedly opens and closes the CD-ROM drive tray.
   
   
3. Hides all the icons on the desktop.
   
   
4. Modifies the value:
   
   "Level" = "1"
   
   in the registry subkeys:
   
   HKEY_CURRENT_USERSoftwareMicrosoftOffice9.0WordSecurity
   HKEY_CURRENT_USERSoftwareMicrosoftOffice10.0WordSecurity
   
   to disable some security settings in Word.
   
   
5. Modifies the value:
   
   "Start" = "3"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesSharedAccess
   
   to modify the Windows Firewall.
   
   
6. Modifies the following values:
   
   "CurrentLevel" = "1"
   "1001" = "0"]
   "1004" = "0"
   "1200" = "0"
   "1201" = "0"
   "1206" = "0"
   "1400" = "0"
   "1402" = "0"
   "1405" = "0"
   "1406" = "0"
   "1407" = "0"
   "1601" = "0"
   "1604" = "0"
   "1605" = "0"
   "1606" = "0"
   "1607" = "0"
   "1608" = "0"
   "1609" = "0"
   "1800" = "0"
   "1802" = "0"
   "1803" = "0"
   "1804" = "0"
   "1005" = "0"
   "1A00" = "0"
   "1A02" = "0"
   "1A03" = "0"
   "1A04" = "0"
   "1A05" = "0"
   "1A06" = "0"
   "1A10" = "0"
   
   in the registry subkey:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionInternet Settingsones3
   
   to lower security setting in Internet Explorer.
   
   
7. Modifies the values:
   
   "UpdatesDisableNotify" = "1"
   "AntiVirusOverride" = "1"
   "FirewallOverride" = "1"
   "FirewallDisableNotify" = "1"
   "AntiVirusDisableNotify" = "1"
   
   in the registry subkey:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftSecurity Center
   
   to disable the Windows Security Center.
   
   
8. Modifies the values:
   
   "DisableTaskMgr" = "1"
   "DisableRegistryTools" = "1"
   
   in the registry subkey:
   
   HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesSystem
   
   to disable the Task Manager and the Registry Editor.
   
   
9. Modifies the value:
   
   "DisableSR" = "1"
   
   in the registry subkeys:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftwindows NTCurrentVersionsystemrestore
   HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionsystemrestore
   
   to disable System Restore.
   
   
10. Adds the value:
    
    "Action" = "Saved"
    
    to the registry subkey:
    
    HKEY_LOCAL_MACHINESoftwareMicrosoftLuderoLedon
    
    
11. Deletes the following files:
    
    
    • C:Program FilesMicrosoft OfficeOfficeExcel.exe
    • C:Program FilesMicrosoft OfficeOfficePowerpnt.exe
    • C:Program FilesOutlook Expressmsimn.exe
    • C:WindowsCalc.exe
    • C:WindowsNotepad.exe
    • C:Program FilesMSN Messenger*.*
    • C:Program FilesMSN Toolbar*.*
      
      
12. Displays a message box with the following properties, on the 3rd, 6th, 9th, 12th, 15th and 18th day of the month:
    
    Title:
    Information
    Message:
    Files deleted.
    
    
13. Copies the active document as the following files, when the infected document is closed:
    
    
    • C:WINDOWSsystem32Dimun.vbs
    • C:WINDOWSsystemDimu.vbs
    • C:WinntSystem32Dime.vbs
    • C:WINDOWSApplication DataMusical.vbs
    • C:WINDOWSHELPMusic.vbs
    • C:WINDOWSFONTSReadme.vbs
    • C:My Shared FolderDinuor.vbs
    • C:Program FilesDinumon.vbs
    • C:WindowsDolun.vbs
    • C:WindowsGirls.vbs
    • C:WindowsGame.vbs
    • C:WindowsWomen.vbs
    • C:WindowsTecnu.vbs
    • C:Dilen.vbs
      
      
14. Copies its code to the Normal.dot file.
    
    
15. Hooks the ToolsMacro() automacro in an attempt to hide its code from the user.

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
• Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. Perform a forensic analysis and restore the computers using trusted media.
• Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.

REMOVAL

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan.
4. Delete any values added to the registry.
5. Restore the Microsoft Word macro security settings
6. Reenable the SharedAccess service (Windows 2000/XP only)
7. Restore the Windows Security Center.
8. Restore the default settings in Internet Explorer.
   

For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• How to disable or enable Windows Me System Restore
• How to turn off or turn on Windows XP System Restore

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:

• Running LiveUpdate, which is the easiest way to obtain virus definitions:
  • If you use Norton AntiVirus 2006, Symantec AntiVirus Corporate Edition 10.0, or newer products, LiveUpdate definitions are updated daily. These products include newer technology.
  • If you use Norton AntiVirus 2005, Symantec AntiVirus Corporate Edition 9.0, or earlier products, LiveUpdate definitions are updated weekly. The exception is major outbreaks, when definitions are updated more often.
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).
  
  The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.

3. To run a full system scan

1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
   • For Norton AntiVirus consumer products: Read the document: How to configure Norton AntiVirus to scan all files.
   • For Symantec AntiVirus Enterprise products: Read the document: How to verify that a Symantec Corporate antivirus product is set to scan all files.
2. Run a full system scan.
3. If any files are detected, follow the instructions displayed by your antivirus program.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode. Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.


4. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.

1. Click Start > Run.
2. Type regedit
3. Click OK.
   
   Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.
   
   
4. Navigate to the subkey:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftLuderoLedon
   
   
5. In the right pane, delete the value:
   
   "Action" = "Saved"
   
   
6. Exit the Registry Editor.

5. To restore the Microsoft Word macro security settings

1. Open Microsoft Word.
2. Select Tools > Macro > Security
3. On the Security Level tab, choose the desired security level.
4. Click OK.

6. To reenable the SharedAccess service (Windows 2000/XP only)
The SharedAccess service is responsible for maintaining Internet Connection Sharing and the Windows Firewall/Internet Connection Firewall applications in Windows. (The presence and names of these applications vary depending on the operating system and service pack you are using.) To protect your computer and maintain network functionality, re-enable this service if you are using any of these programs.


Windows XP Service Pack 2
If you are running Windows XP with Service Pack 2 and are using the Windows Firewall, the operating system will alert you when the SharedAccess service is stopped, by displaying an alert balloon saying that your Firewall status is unknown. Perform the following steps to ensure that the Windows Firewall is re-enabled:

1. Click Start > Control Panel.
   
   
2. Double-click the Security Center.
   
   
3. Ensure that the Firewall security essential is marked ON.
   
   Note: If the Firewall security essential is marked on, your Windows Firewall is on and you do not need to continue with these steps.
   
   If the Firewall security essential is not marked on, click the "Recommendations" button.
   
   
4. Under "Recommendations," click Enable Now. A window appears telling you that the Windows Firewall was successfully turned on.
   
   
5. Click Close, and then click OK.
   
   
6. Close the Security Center.

Windows 2000 or Windows XP Service Pack 1 or earlier
Complete the following steps to re-enable the SharedAccess service:

1. Click Start > Run.
2. Type services.msc
   
   Then click OK.
   
   
3. Do one of the following:
   
   • Windows 2000: Under the Name column, locate the "Internet Connection Sharing (ICS)" service and double-click it.
   • Windows XP: Under the Named column, locate the "Internet Connection Firewall (ICF) / Internet Connection Sharing (ICS)" service and double-click it.
     
     
4. Under "Startup Type:", select "Automatic" from the drop-down menu.
   
   
5. Under "Service Status:", click the Start button.
   
   
6. Once the service has completed starting, click OK.
   
   
7. Close the Services window.

7. To restore the Windows Security Center
This risk attempts to disable the features in the Windows Security Center, available in Windows XP Service Pack 2. If you are running Windows XP Service Pack 2 and would like to restore the full functionality of the Windows Security Center, please complete the following steps:

Important: If your computer is connected to a domain, you may not be able to adjust these settings. If so, contact your network administrator for more information.

1. Click Start > Control Panel.
2. Double-click the Security Center.
3. In the right pane, click Windows Firewall. The Windows Firewall appears.
4. Select On.
5. Click OK to close the Windows Firewall.
6. In the left pane of the Security Center, select Change the way Security Center alerts me.
7. Click Alert Settings.
8. Select Alert Settings, Firewall, and Virus Protection.
9. Click OK
10. Click Automatic Updates.
11. Select Automatic.
12. Click OK.
13. Exit the Security Center.

8. To restore the default settings in Internet Explorer

1. Click Start > Settings > Control Panel
2. Select Internet Options
3. Select the Programs tab
4. Click Reset Web Settings
5. Click OK
6. Exit the Control Panel